EUROPE: Scientists urge action on ocean acidity
That has negative effects on marine life. For example, shellfish and corals find it more difficult to form their shells and external skeletons because the concentration of calcium carbonate in seawater drops as it becomes more acidic.
Earlier this month, the European Science Foundation delivered an overview of the impact of ocean acidification for European Maritime Day.
Prepared by leading scientists from Europe and the US, it highlights the need for a concerted, integrated effort internationally to research and monitor the effects of ocean acidification on marine environments and human communities.
"Ocean acidification is already occurring and will get worse. And it's happening on top of global warming so we are in double trouble," said Professor Jelle Bijma, lead author of the report and a bio-geochemist at the Alfred Wegener Institute in Germany.
"The combination of the two may be the most critical environmental and economic challenge of the century," he said.
"Under a business-as-usual scenario, predictions for the end of the century are that the surface oceans will become 150% more acidic - and this is a hell of a lot."
But integrated research on the impacts of ocean acidification is still a very new field - the full implications of rising acidity is unclear for marine ecosystems and fisheries resources, including fish stocks, shellfish and coral reefs.
Current European and national research programmes are relatively small compared to the combined challenges posed by ocean acidification and global warming. Existing research has mainly been initiated by individual researchers or teams, with limited overall coordination.
Two years ago, the European Project on Ocean Acidification was funded by the EU and within the last year Germany and the UK have funded national ocean acidification programmes - Bioacid and the UK Ocean Acidification Research Programme respectively.
The European Science Foundation says that as others emerge they need to be brought together through a large-scale research initiative taking full advantage of the combined scientific expertise across the European countries and internationally. One of the first steps toward integration is to develop a specific database building on the national research activities in ocean acidification.